This documentation explains how you can contribute to EasyBuild, and discusses the review process for contributions.

How to contribute

It is a common misconception that contributing to an open source project requires being intimately familiar with its codebase.

There are various ways to contribute, even if you don’t have any experience with the programming language(s) being used by the project you are interested in.

You can contribute to EasyBuild by:

Giving feedback

An easy way to contribute to EasyBuild, even without having a lot of hands-on experience with it, is to provide feedback on your experiences.

Feedback from people new to EasyBuild is valuable, since it provides a perspective that is easily overlooked by more experienced users.

You can contact the EasyBuild community via the EasyBuild mailing list (, the #easybuild IRC channel (see also Getting help).

Reporting bugs

If you run into unexpected problems when using EasyBuild, please open a bug report in the issue tracker of the relevant GitHub repository:

Please try and provide all relevant information, which may include:

  • the EasyBuild version you are using
  • the specifics of the system you are using, incl. OS + version, Python version, modules tool & version, etc.
  • the active EasyBuild configuration; usually the output of eb --show-config is sufficient
  • the full eb command line that was used
  • warning or error messages, or other relevant informative messages
  • filename or contents of easyconfig file(s) being used
  • EasyBuild log file (for example via, preferably collected with eb --debug

Submitting feature/change requests

If you have suggestions for enhancements or ideas for new features that could be useful, please open an issue in the relevant GitHub repository (see Reporting bugs).

Describe what you have in mind, and maybe also provide a concrete example to illustrate how your suggestion would improve the current functionality.

Helping others

Try and help others based on your experience, or help them figure out an answer to their question or a solution to their problem using the EasyBuild documentation or by reaching out to someone else in the EasyBuild community that may know the answer.

The EasyBuild community is known to be very welcoming and helpful, and you too can be a part of that.

Contributing easyconfig files

Please contribute easyconfig files that are not included yet in (the develop branch of) the easybuild-easyconfigs GitHub repository at

This includes easyconfigs for software that is not supported yet by EasyBuild, as well as updates to existing easyconfigs (e.g., version updates, using a different toolchain, etc.), even if you consider the updates to be trivial. Keep in mind that being able to use something that is known to work out-of-the-box can save quite a bit of time compared to having to tweak existing easyconfigs and validate the result installations.

We highly recommend using the --new-pr and --update-pr command line options for contributing easyconfig files; see Submitting new and updating pull requests (–new-pr, –update-pr).

Contributing code changes

Of course you can also contribute code changes, including bug fixes, enhancements or additional features in the EasyBuild framework, the easyblocks repository, the test suites or in related scripts.

Do keep in mind that this requires some experience with Python, although you should be able to go a long way by using the existing code base as support.

See Pull requests for more information on the practical aspects of contributing code.

Writing documentation

Another way to contribute to EasyBuild without having to implement Python code is by writing documentation, i.e. enhancing or updating existing documentation or documenting features that are not covered yet.

To contribute to the documentation hosted at, you should open a pull request to the develop branch of the main EasyBuild repository at; see the docs subdirectory.

A particularly useful tool is, which can be used to preview how the documentation written in reStructuredText format will be rendered on (select the Nature theme for optimal results).

Joining the conversation

Last but not least, you can actively join the conversation that arise on the EasyBuild mailing list, the #easybuild IRC channel and during the bi-weekly EasyBuild conference calls (see

Engage with the EasyBuild community, and help steer EasyBuild development by participating in the conversations regarding a variety of topics related to building and installing (scientific) software.

Pull requests

To contribute to the EasyBuild framework, easyblocks, easyconfig files or the EasyBuild documentation, you will need to open a pull request to the corresponding GitHub repository:

Doing this the traditional way requires some knowledge about using git (i.e. creating commits, using branches, pushing to and pulling from remote Git repositories, etc.), and being familiar with GitHub.

However, this can be largely circumvented by using the GitHub integration provided by EasyBuild, see :ref:`integration_with_github`.

Setting up


These instructions assume that you already have a working GitHub account.

If you don’t have a GitHub account yet, visit to create one.

We highly recommend registering your SSH public key in your GitHub account, via This allows pushing to your fork of the GitHub repositories without using a password.

Before you can open pull requests, you will need to fork the GitHub repository you are targeting, and create a local working copy of that repository. This only needs to be done once for every of the EasyBuild repositories.


For the purpose of this guide, we will be using the easybuild-framework repository.

However, the instructions are equivalent for the other EasyBuild repositories.

Forking the repository

First, create your own fork of the repository in your GitHub account using the ‘Fork‘ button on the top right at

This will create a ‘copy’ of the easybuild-framework repository owned by the easybuilders GitHub organisation to your own personal GitHub account.

You will have to use this fork as a staging area for your work, to prepare your contributions before creating the actual pull requests.

Creating a working copy


Do not forget to replace ‘EXAMPLE‘ with your GitHub account name in the instructions below.

In addition to forking the repository on GitHub, you also need to create a local working copy of the repository. This is basically a local checkout of the repository where you can track the changes you are making.

First, clone your fork of the repository:

git clone

If that worked as expected, you should have a new directory named easybuild-framework. Move into the easybuild-framework directory:

cd easybuild-framework

Finally, we recommended to also check out the develop branch, which will be used as the base for your own branches:

git checkout -b develop origin/develop

With this in place, you are all set to open pull requests for your contributions.

Keeping the develop branch in sync

It is important to keep the develop branch in your working copy in sync with the upstream repository in the GitHub easybuilders organization.

For this, you need to add the upstream repository as a ‘remote‘ repository:

git remote add upstream


upstream‘ is just a name that you give to the remote the central easybuilders repository on GitHub; you can modify this to your liking if desired (but do take that into account for the further instructions if you do so).

For your fork of the repository, a default remote named origin should have been created via git clone (see the output of git remote -v).

To sync your develop branch, use git pull upstream develop after making sure you have the develop branch checked out:

git checkout develop
git pull upstream develop

Opening a new pull request


This section describes the manual procedure to open a new pull request.

Please consider using eb --new-pr instead, see Submitting pull requests (–new-pr).


We assume you are already located in your local working copy of the repository you want to contribute to (e.g., easybuild-framework).

To open a pull request for your contribution, you must follow these steps:

  1. Creating a new branch
  2. Committing your changes
  3. Pushing your branch
  4. Pull request title & description
  5. Opening the pull request

Creating a new branch

First, create a new branch for your work. You can do this either before or after making the changes that you would like to contribute, but we recommend to create a new branch before making any changes.

Make sure you have the develop branch checked out before creating your branch:

git checkout develop

To create a new branch, you should use git branch <branch_name> followed by git checkout <branch_name>, or equivalently git checkout -b <branch_name>.

For example, to create a new branch named mybranch:

git checkout -b mybranch

You can choose the branch name freely, but make it sufficiently descriptive – your future self will thank you.

Committing your changes

To ‘save’ your changes, you should create one or more commits in the branch you created. We recommended making separate commits for different ‘units of work’.

First, make sure you have checked out the branch were you want to commit the changes to. For example, to prepare for committing changes to the mybranch branch:

git checkout mybranch

To check which branch is currently checked out, use git branch.

To get a high-level overview of the changes before committing them, you can use git status.

To see the actual changes that were made, use git diff.

To commit the changes you want to contribute, use git add <files> to stage the changes, followed by git commit -m "<message>" to create the actual commit.

For example, to commit the changes that were made to easybuild/tools/

git add easybuild/tools/
git status  # check which files are staged for commit
git commit -m "example commit message for changes to"


Please use a concise commit message that describes the changes you made.


For files that are already being tracked, you can use git commit -am <message> to commit all changes at once.

To verify that your work was committed, use git log to see all commits on the current branch. Use git log --stat and/or git log --diff to see more details about which changes are included in each of the commits.

Pushing your branch

Once you have committed your changes to a branch, you should push your branch to your fork of the GitHub repository using git push.

For example, to push the mybranch branch to your fork of the GitHub repository (via the origin remote, see Creating a working copy):

git push origin mybranch

Note: this will make your work public.

Pull request title & description

Please use a descriptive (short) title for your pull requests, and clarify (if needed) in the pull request description.

If any other pull requests are required, refer to them in the description using #<PR number> (only for pull requests to the same repository), or by copy-pasting the URL to the pull request.

For pull requests to the easyconfig repository, we recommend using this format for the pull request title when contributing new easyconfig files:

{<moduleclass>}[<toolchain>] <software name> <software version> <extra info>

For example:

  • {tools}[dummy] EasyBuild v3.2.1
  • {math}[intel/2017a] numpy 1.13.0 w/ Python 2.7.13
  • {math,numlib}[foss/2017a] METIS v5.1.0, ParMETIS v4.0.3, SuiteSparse v4.5.5, ...

If you are opening a work-in-progress pull request, for example to solicit feedback, tag it using (WIP). in the pull request title.

Opening the pull request

To open a pull request using the branch you pushed, you should use the GitHub interface, and follow the steps outlined below.


Replace ‘EXAMPLE‘ with your GitHub account name, and ‘easybuild-framework‘ with the name of the target EasyBuild repository.

  1. visit;
  2. switch to the branch that includes the changes you want to contribute using the ‘Branch: master‘ button on the left, for example by selecting Branch: mybranch from the dropdown list
  3. click the ‘New pull request‘ button;
  4. change the target branch to develop using the ‘base: master‘ button;
  5. review your changes using the ‘diff’ view presented by GitHub;
  6. provide an appropriate title and description for your contribution;
  7. open the pull request by clicking the green ‘Create pull request‘ button

Next, your pull request will be reviewed & tested, see Review process for contributions.

Updating existing pull requests


This section describes the manual procedure to create a new pull request.

Please consider using eb --update-pr instead, see Updating existing pull requests (–update-pr).

It is quite common to update a pull request after creating it, for example if Travis reports problems with the changes being made, or as a response to someone reviewing your contribution.

To update an existing pull request, it suffices to add commits to the branch that was used for opening the pull request, and pushing the updated branch to GitHub.

For example, to update the pull request that was created using the mybranch branch:

git checkout mybranch
# make changes...
git add <paths to changed files>
git commit -m "example commit message for additional changes"
git push origin mybranch

Updating a pull request will trigger Travis to re-test your contribution, and a notification will be sent out to whoever is ‘watching’ your pull request.

Merging of pull requests

Once your pull request has been given the green light by Travis and one or more people reviewing have approved the changes, it can be merged into the develop branch.

This can only be done by a member of the EasyBuild maintainers team. Only pull requests that meet the requirements are eligible for merging, see :ref:`contributing_review_process_pr_requirements`.

Merging a pull request usually implies that the changes will be part of the next EasyBuild release.

Review process for contributions

Each contribution is thoroughly reviewed and tested before it gets merged in. Some aspects of this are automated, others require human intervention.

Requirements for pull requests

Only pull requests (PRs) that fullfil these requirements are eligible to be merged:

  1. the PR must target the develop branch of the repository; see develop branch
  2. the test suite must (still) pass, i.e. Travis must give a green light; see Test suite (Travis)
  • tests should be added or enhanced when appropriate; see Adding tests, especially for PRs to the easybuild-framework repository
  1. backward compatibility should be retained; see Backward compatibility
  2. code style must be kept consistent; see Code style review
  1. (successful) test reports must be submitted for easyconfig PRs; see Test reports for easyconfig contributions (upload-test-report)
  1. the PR is approved by one or more maintainers of the repository; see EasyBuild maintainers
  2. the PR should be merged by one of the maintainers, other than the author of the PR; see Pull requests are merged by a maintainer other than the author

develop branch

Pull requests are only merged in thedevelopbranch of the EasyBuild repositories, which contains the changes that will be included in the next EasyBuild release.

The ‘master‘ branch provides the latest stable release of EasyBuild at all times. Only the EasyBuild release manager should issue a pull request to the EasyBuild ‘master‘ branch, when preparing a new EasyBuild release.

Occasionally, an additional version branch (e.g. ‘3.3.x‘) may be introduced temporarily, in case an intermittent bugfix release is being worked on.

Test suite (Travis)

Each pull request is tested automatically by Travis and the test result is reported in the pull request.

Only pull requests that have been tested and approved by Travis are eligible for being merged!

Note that Travis will only run the test suite for that particular repository. That is, for easyconfig contributions it does not include actually building and installing software.

For more information on the test suites, see Unit tests.

Adding tests

An implicit requirement for contributions, in particular contributions to the EasyBuild framework, is that they must be accompanied by additional tests or test cases.

For new features or enhancements, a dedicated test (case) must be added which verifies that the feature implementation works as expected.

For bug fixes, a test (case) must be added that triggers the code path where the bug manifested, and which verifies that the bug was indeed fixed.

Tests not only confirm that the implementation is correct, it also helps to ensure that any future changes will not break the functionality you contributed.

Backward compatibility

Contributions should retain backward compatibility, i.e., they should not make any changes that alter the (default) functionality of the existing code base. Of course, enhancements to existing code that retain backward compatibility can be made.

One exception to this rule is bug fixes, where the whole point is usually to fix functionality that was implemented incorrectly.

This also applies to existing easyconfig files; for example, the versions of dependencies should not be altered. Adding dependencies that were missing or otherwise enhancing existing easyconfigs (e.g., adding extra extensions, enabling additional features, etc.) are usually considered acceptable.

Changes that break backward compatibility have to be motivated well with technical arguments, and must be approved by the EasyBuild maintainers.

Code style review

Next to functional evaluation of contributions, care is also taken to maintain a consistent code style across the EasyBuild code base (see also Code style); contributions must take the (mostly PEP8) code style into account.

This aspect is sometimes considered to be needless overhead, yet it is an important aspect of the review process. A consistent code style is invaluable in a large code base that is constantly being updated by a worldwide community.

This also applies to easyconfig files, where we try to maintain a strict style that mostly matches the established PEP8 coding style for Python (since easyconfigs are written in Python syntax). However, also the grouping and ordering of easyconfig parameters is a part of the ‘code’ style we maintain.

An automated (partial) style check on easyconfig files can be performed via eb --check-style, and is also a part of the test suite run by Travis for easyconfig PRs.

Comparing with existing easyconfigs (--review-pr)

We try to maintain consistency across easyconfig files for a particular software package, across multiple software versions, toolchains and variants (with a different versionsuffix).

Therefore, easyconfig contributions are also reviewed using eb --review-pr <PR #>, which compares the touched easyconfig files to those in the current develop branch that are most closely related.

The easyconfig files to compare with are selected based on similarity, by combining two criteria, in order.

First, the software version is taken into account, using one of the following criteria:

  • exact match on software version match
  • match on major/minor software version
  • match on major software version
  • no match on software version

This is combined with one of the criteria below (in order):

  • matching versionsuffix and toolchain name/version
  • matching versionsuffix and toolchain name (any toolchain version)
  • matching versionsuffix (any toolchain name/version)
  • matching toolchain name/version (any versionsuffix)
  • matching toolchain name (any versionsuffix, toolchain version)
  • no extra requirements (any versionsuffix, toolchain name/version)

The first combination of one of the software version criteria with one of the other criteria that yields one or more matching easyconfig files is used. If none of the combinations match, no easyconfig files for that particular software package are available yet, and no comparison is made.

The output of --review-pr provides a ‘multidiff’ comparison, which highlights the differences between the easyconfig file in the pull request and the most similar selected ones from the current develop branch.

For example:

Interpreting this output is a quick and easy way to assess how different the contributed easyconfig files are from the existing easyconfigs, although it does require a bit of practice because of the density of the provided information.

Test reports for easyconfig contributions (upload-test-report)

For easyconfig contributions, one or more accompanying test reports must be submitted to confirm that the added and/or changed easyconfig files (still) work as expected.

We recommend that you submit a test report for your own easyconfig pull requests. Other people can also submit test reports to confirm that your contribution works as expected on their system(s).

With EasyBuild being properly configured (see Configuration), this should be as simple as running eb --from-pr <PR#> --upload-test-report --force --robot.

See Uploading test reports (–upload-test-report) for more information.

Pull requests are merged by a maintainer other than the author

A pull request should never be merged by its author.

This policy is maintained in order to ensure a “two-pairs-of-eyes” review process of all contributions.